This study is designed to investigate the catabolism of methionine in lactic acid bacteria to produce methanethiol. Two pathways are involved in the catabolism: 1) ?,?-elimination by cystothionine ?-lyase and 2) transamination. 13C NMR using the DMX 400 MHz spectrometer should yield a way to differentiate between the two pathways as well a the possible distribution between the two pathways.